A silicone compound can confer unique slipping property and feel on fiber products and is thus widely used in fiber product treating agents. As described in JP-A 2007-46171, JP-A 5-508889, JP-A 2001-279581 and JP-A 2000-110076, fiber product treating agents based on a silicone compound have been examined in recent years as treating agents used in a washing process at home.
Meanwhile, polyester-based polymer compounds containing an alkylene terephthalate and alkylene isophthalate as structural units are known as a soil release agent and applied to detergents etc. For the purpose of industrially conferring a soil release effect on fiber products, JP-A 9-291483 discloses techniques of simultaneously using a polyester polymer compound and a polyether-modified silicone.